// Problem: 
// Contest: 
// URL: 
// Memory Limit: 
// Time Limit: 
// #pragma GCC optimize("Ofast")
// #pragma GCC optimize("unroll-loops")
// #pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,avx2,tune=native")
#include<bits/stdc++.h>
using namespace std;
#define int long long
inline int read(){
	int s=0,w=1;
	char ch=getchar();
	while(ch<'0'||ch>'9'){if(ch=='-')w=-1;ch=getchar();}
	while(ch>='0'&&ch<='9') s=s*10+ch-'0',ch=getchar();
	return s*w;
}
signed main()
{
	char c;
	int stk[1000];
	int i=0,now=0;
	while((c=getchar())!='@')
	{
		if(c>='0'&&c<='9')now=now*10+c-'0';
		else if(c=='.')stk[++i]=now,now=0;
		else if(c=='+')stk[i-1]+=stk[i],stk[i--]=0;
		else if(c=='-')stk[i-1]-=stk[i],stk[i--]=0;
		else if(c=='*')stk[i-1]*=stk[i],stk[i--]=0;
		else if(c=='/')stk[i-1]/=stk[i],stk[i--]=0;
	}
	cout<<stk[1];
	return 0;
}
